1. Field of the Invention
This invention relates to improvements in an optical recording/reproducing apparatus wherein it is judged whether an optical recording medium has been used or not and data are recorded or reproduced.
2. Description of Related Art
Recently there has come to be practiced an optical recording/reproducing apparatus wherein, by condensing and radiating a light beam, for example, of a laser light on an optical recording medium, for example, through an optical system lens, data are recorded in the recording medium in which, for example, a hole is made or, by the reflected light from the above described hole, the recorded data can be reproduced. In the following, a disc-like optical disc shall be described as an example of the above mentioned recording medium.
The above mentioned optical disc is formed of a synthetic resin or the like to be substantially like a disc of a diameter, for example, of about 30 cm and is characterized in that the shape is small and the data memorizing capacity is large. Therefore, the optical disc driving apparatus recording/reproducing data in this optical disc is used as an auxiliary memorizing apparatus in such computer system as, for example, an image filing system.
In the case of recording data in this optical disc, if the optical disc is divided, for example, into sector units and a physical position (called a physical address hereinafter) is designated to each sector, writing will be made to the physical address of the usually used sector and, in order to judge whether this writing is accurately made or not, just after this writing, there will be made a collating operation of reading and collating the physical address and data. The timing of the writing and reading is that the writing will be made when the above mentioned sector is positioned in an optical head writing data into the above mentioned optical disc and the reading will be made when the above mentioned sector is positioned in an optical head reading data out of the above mentioned optical disc. That is to say, in case the writing optical head and reading optical head are the same, when the optical disc makes one rotation, a collating operation will be made. Also, the physical address is usually a combination of a track which is a peripheral position of the above mentioned optical disc and a sector number given to each of the sectors dividing the track number given to this track into a predetermined number.
In the above described collating operation, a writing error may be generated in case the written data can not be detected or in case an error exceeding the range which can be corrected is generated even though it is intended to correct errors of the read data. Also, in case the above described writing is to be carried out, a writing error which cannot detect the physical address of the usually used sector may be generated.
Therefore, the physical address of the sector which is an alternate of the physical address of the usually used sector is determined and an alternating process for writing into this alternating sector the contents of the sector in which a writing error has been generated is carried out. This alternating sector may be a sector near the usually used sector or may be a separately determined sector separated from the usually used sector.
In case the above described alternating process is made, data mentioning the contrast of the physical address of the usually used sector and the physical address of the alternating sector will be recorded in a predetermined physical address of the above mentioned optical disc.
For example, SDL (Secondary Defect List) formats mentioning the physical addresses in the above mentioned optical disc recording data mentioning the contrast of the physical address of the usually used sector and the physical address of the alternating sector are regulated in 14, 4, 3 and 3 of ISO/IEC JTC1/SC23N292 of ISO (International Standardization Organization). According to this, the above mentioned SDL is regulated to be provided in four places in an optical disc system controlling area.
It is suggested in the publication, for example, of Japanese Patent Application Laid Open No. 205741/1985 that, in case the above described alternating process is made, data mentioning the contrast of the physical address of the usually used sector and the physical address of the alternating sector will be recorded in the above mentioned optical disc.
In case the above described alternating process is generated, the above mentioned SDL will be renewed.